Design And Research Of 1.3μm GeSi/Si Heterostructure Optical Waveguide Coupler

In order to resolve more massive scale and higher speed of transmission of information in electronic system into reality,one way is that higher speed electronic devices are adopted ,the other way is that optical waveguide deivices are introduced to connect chips. GeSi/Si heterojunction has more superiority in the mauufacture of high speed electronic devices and optical waveguide devices.This thesis proves the superiority and the necessity of design and manufacture of GeSi/Si heterojunction optical waveguide couplers,and deeply research and discuss the grating coupler and the bragg reflection grating from GeSi/Si heterostructure materials property , energy-band structure,transmission light characteristic,measurements and structure of devices and technology ect..Firstly, this thesis analyzes GeSi/Si heterojunction transmission light characteristic in light of it's energy-band structure, provides percentage that each ingredient occupied,let the intrinsic absorption limit of GeSi alloy be above 1.3μm, then obtains the refractive index of the waveguide layer, and designs the thickness of the waveguide layer.Secondly,according to the coupling theories and using MATLAB, calculates the radiation coefficient of GeSi/Si heterojunction grating coupler and the coupling coefficient of GeSi/Si heterojunction bragg reflection grating,then designs the size of the grating period, the grating length,the grating width, the groove depth and the tooth width. The numerical simulation of the distribution of the electronic field in the two sorts of devices are given. The design of 1.3 ? GeSi/Si heterojunction coplanar and single mode Bragg reflection grating is presented, the results are as following: the incident angle is 66 o the guide thickness is 2?,the coupling width is 4252 ?, the groove depth is 0.05 ?,the period is 0.456 ?, the wavelength selectivity is 2.14 A0, the coupling efficiency is 84.1%. Acccording to Tamir's theories, 1.3 ? GeSi/Si heterojunction waveguide grating coupler is approxiamately designed,the results as following : the guide thickness is 2 ? ,the groove shape is asymmetry rectangle section ,the grating length is L = 3mm,the grating periodΛ≈0.51μm and the groove depth is hc = 0.085μm,the input coupling efficiency is 29%,the output coupling efficiency is 37%. The coupling length,the period and the groove depth of the Ge 0. 05Si 0. 95/Si heterostructure optical waveguide grating coupler is designed and analyzed of which guide thickness is 2500nm and wavelength is 1300nm .The results are as following:when the incident angle is 75o in air (the incident angle is 160 in the substrate),the period is 0.512μm,the groove width is 0.256μm,the coupling length is 2.3mm,the input coupling efficiecy in air is 22.5% ,the input coupling efficiency in the substrate is 46.3%;the output coupling efficiecy in air is 28%, the output coupling efficiency in the substrate is 57.8%.The manufacture technology and measurement are deeply studied ,main technology includes MBE,two beam interference method,electron-beam lithography and plasma etching ect.Through prism coupling method and grating coupling method,transmission constant and coupling efficiency are measured.